Simon Gillett said the estimated cost of re-building was now £80m
The British Grand Prix is to stay at Donington Park for the next 17 years, it has been claimed.
Simon Gillett, of Donington Park Ventures, said the Formula 1 chief Bernie Ecclestone had agreed to an extension of its original 10-year deal.
And the cost of turning the venue into an F1 site has dropped from £100m to about £80m, Mr Gillett said.
The recent Download music festival showed Donington could handle large numbers, he added.
Mr Gillett said: "Bernie Ecclestone's agreed to give us a seven year extension, so we're now at 17 years running from 2010.
"That's a nice rubber stamp from Bernie himself to say he believes in Donington and he wants to have a long-term relationship with it.
"The cost of the build is now about £80m but we've been through the value engineering process and worked out some of the costs.
"Because of the credit crunch the cost of building has come down in price, so put all that together and we're at about £80m now."
The Download festival which 135,000 fans attended, showed how well Donington Park would be able to handle the increased demands of a Formula One crowd, Mr Gillett said.
Donington Park secured the British Grand Prix at the expense of current hosts Silverstone and is due to stage its first Formula One Grand Prix since 1993 in July 2010.